Corn can withstand periods of early-season water stress, but drought during pollination and grain fill can significantly reduce kernel development and final yield, according to Pioneer territory manager Ron Joiner.
Water plays a critical role in moving nutrients into and throughout the plant. When soil moisture is limited, nutrient uptake declines, increasing the likelihood of yield loss. Joiner said the severity and duration of drought are the most important factors influencing production losses.
When roots cannot access nutrients because of dry soils or restricted root growth, corn plants begin remobilizing nutrients from other plant tissues. This can reduce kernel rows, kernel weight and stalk strength while increasing the risk of kernel abortion. Drought-stressed kernels often become small, shriveled and lightweight, reducing both harvest efficiency and grain quality.
Joiner noted that yield losses can continue even after pollination. Reduced kernel depth and kernel weight remain major contributors to lower yields during grain fill when moisture is insufficient.
Hybrid selection also plays an important role in minimizing drought impacts. Hybrids with improved water-use efficiency can help maintain yield potential across varying environments. In lower-yielding dryland conditions, growers often reduce plant populations, although the response varies by hybrid.
Drought-tolerant hybrids, including Pioneer Optimum AQUAmax products, can provide greater flexibility for managing production risk in water-limited environments while maintaining the ability to capitalize on favorable moisture later in the season.
As drought stress continues, crop conditions can decline rapidly because of standability and grain quality issues. If wet weather follows prolonged drought, deterioration can accelerate. Dry down also occurs quickly, and grain moisture below 15% can reduce the amount of marketable grain.
During harvest, growers should adjust combine settings to account for small, rubbery cobs and lightweight grain. Air settings should be carefully reduced to remove light material without blowing grain from the machine, and equipment should be checked frequently as crop conditions change.
Because drought conditions and crop response can vary throughout the growing season, regular field monitoring can help growers identify emerging risks and make timely management decisions.
Corteva Agriscience recently introduced In-Season Monitoring, a Decision Science tool designed to provide information on corn growth stages, local environmental conditions and emerging disease risks. The platform also tracks growing degree units, precipitation and solar radiation throughout the season and compares current conditions with five-year averages to support management decisions.
Source: Michigan Farm News, "Understanding corn’s most critical drought window"